In 1956 the responsible investigator, with M.J. Karvonen, conducted medical surveys in Finland which included measurement of cholesterol in the alpha and beta lipoproteins separated by paper electrophoresis. Sampling in east and west Finland provided data on 869 clinically healthy men then aged 20 to 60. Some findings were published in the Lancet July 26, 1958. Finland has a very high mortality from coronary heart disease which we verified in the Seven Countries Study (started in 1959 in Finland). It is estimated that by 1980 about 380 of our men of 1956 will be dead, 140 from coronary heart disease. It is proposed to ascertain the deaths and their causes, using the excellent Finnish death, citizenship, and National Pension System records. Staff members of the Finnish Heart Association will cooperate. Analysis of relationships of the 23-year mortality with 1956 characteristics should illuminate the significance of the known risk factors and the theory that high density lipoproteins protect against coronary heart disease. Alpha and high density lipoproteins are essentially identical.